Toolholder for drill presses and the like



Sept. 5, 1950 E. M. KURTZ ET AL 2,521,585

TooLHoLDER FOR DRILL PREssEs AND THE LIKE Filed Oct. 1B, 1948 VTOREK Patented Sept. 5, 1950 OFFICE TOOLHOLDER FOR DRILL PRESSES AND THE LIKE Earl M. Kurtz and Joseph B. Houston, Kansas City, Mo.

Application October 18, 1948, Serial No. 55,042

(Cl. 'i4- 750) Claims.

This invention relates to machinists tools and more particularly to an instrumentality forming a driving connection between a pair of rotatable shafts, the primary object being to provide means for transmitting rotative motion to a driven shaft in either of two directions while the drive shaft rotates in a single direction, all to the end that the speed of rotation of the driven shaft can be lVaried and, further to the end that a positive drive is eliminated, thereby eliminating breakage of parts connected to and worked upon through the driven shaft.

The most important object of this invention is to provide'a device capable of being interposed between a drive shaft, such as a shank extending from a drill press or lathe chuck, and a driven shaft having a second chuck thereon for receiving a tap or analogous tool, the device being shiftable as a unit longitudinally relative to the axes of rotation of the shafts for moving parts thereof to and from frictional engagement with the drive shaft, whereby to rotate the driven shaft in either of two directions.

Another important object of this invention is to provide a rotatable drive Shaft having a boss intermediate the ends thereof and a plurality of rotatable members circumscribing the drive shaft and having driving connection with the driven shaft, all to the end that, as the rotatable elements are brought into frictional engagement with said boss, the driven shaft is actuated thereby.

A further object of this invention is to provide a device of the aforementioned character having a second set of rotatable elements circumscribing the drive shaft on the opposite side of the boss thereof, said second set of elements also having driving connection with the driven shaft, to the end that the latter may be rotated in the opposite direction upon proper relative reciprocation of the drive shaft and the entire device as a unit.

A still further object of this invention is to provide a hollow body having a pair of annular races formed therein, one of the races being integral with the body, the other being rotatable relative thereto, said races having rotatable elements -carried thereby for operating the driven shaft through frictional engagement between the rotatable elements and the drive shaft either through a revolving action of one set of rotatable elements or upon rotation of one of the members having a race formed therein with respect to the body.

Y Other more minor objects will be made clear as the following specification progresses, reference being had to the accompanying drawing, wherein:

Fig. 1 is a perspective view of a tool holder for drill presses and the like made in accordance with our present invention, showing one operative use thereof.

Fig. 2 is an enlarged, substantially central, longitudinal, cross sectional view taken on line II-ll of Fig. 1.

Fig. 3 is a transverse, cross sectional View taken on line III-i111 of Fig. 2.

Fig. 4 is a transverse, cross sectional view taken on line IV--IV of Fig. 2.

Fig. 5 is a transverse, cross sectional view taken on line V-V of Fig. 2; and,

Fig. 6 is a, transverse, cross sectional View taken on line VI--VI of Fig. 2, looking in the direction of the arrows.

The device about to be described has been produced primarily to overcome present-day difficulties experienced by machinists in tapping operations. Breakage of taps and damage to the work itself is quite common, particularly when relatively small taps are being used, because of the fact that the drill press or other instrumentality used to rotate the tap imparts a positive drive to the tool and the operator is unable to determine when too much pressure is being applied. Consequently, for the most part, whenever a small tapping operation is to take place, the same is conducted by hand. Obviously, this method of tapping small pieces of work is slow,

tedious and somewhat diilcult.

It will become apparent that the instrumentality forming the subject matter hereof will eliminate all of the aforesaid diiiiculties and permit a tapping operation through use of the conventional drill press or like mechanism, irrespective of the relative small size of the tap. Inasmuch as the driving connection forming the subject matter hereof can be controlled by the operator and is purely frictional, any binding that might occur between the tap or other tool and the work itself will immediately cause a cessation of tap rotation and thereby eliminate breakage and other damage.

In the drawing, there is illustrated an elongated tubular body l0 having both ends thereof initially open, said ends being closed by a pair of opposed plugs i2 and I4, respectively. rlhe plug l2 is provided with a central opening I6 for receiving a, bushing I3 that, in turn, rotatably and slidably receives an elongated shaft 29.

. The uppermost end of shaft 2B is received by a chuck 22 or other releasable joining structure forming a part of a conventional drill press 23, lathe or other machine capable of imparting rotative movement to the shaft 20. Obviously, the chuck 22, as well as the driving connection therefor, forms no part of this invention.

The outermost end of the opening I6 within plug I2 is enlarged. as indicated in Fig. 2 of the drawing, for receiving a suitable washer 24 formed from material capable of maintaining shaft 20v properly lubricated within bushing I8 and, at the same time, prevent entrance of dust and other foreign particles into body I0. Both of the plugs I2 and i4 are removably held secured within body I through the medium ofa plurality of screws or the like 26.

The plus I4 isy likewise, nrevided with a central opening 28 for rotatably receiving a tubular member 20, which, in turn, receives a tubular bushing 32. 36 in opening 28, to. the end that shaft 24v becomes selfecentering in body IIl, thereby eliminating binding. A stub shaft 34 is secured to the member 3u by press flt orother means and extends outwardly from the outermost end thereoffoy. receiving a chuck 36. The relatively small chuck 36 may be fastened to the outermost end of stub shaft 34 in any suitable manner and is of conventional character for receiving a tap 3-8 or other machinists tool to be rotated by rotation of shaft 34 and, consequently, chuck 36'.

A ring-like member 33 is rigidly secured within body- E5. intermediate the ends thereof and is provided with an annularrace 40 that circumscribes the drive shaft 20 adjacent the innermost end thereof, said race 40 receivingl a plurality or rotatable elements 42l which, in the instance Vshown, constitute spherical members. There are three of the spherical members 42-- disposed within the race 40, as indicated in Fig. of the drawing, but the number thereof is im material to this invention.

Fig. 4, also, illustrates the way in which these .rotatable elements 42- are disposed between the raceA 40 and the shaft 2Q in relatively close relationshipthereto but provided with suliicient clearance topermit free rotationofshaft with respect tothe elements- 42.

The rotatable, tubular member 3-0 is provided with an out-turned flange 44 at the innermost end. thereof, saidflange beingdisposed between the racemember-S and. the plug I4; This flange 44 is providedV witha number`l of openings 46, for receiving a lowermost endl of a stub 48 that is heldin` placeby a screw or the-like 501.

There are three of these stubs 48: and; consequently, threeopenings` 46 and screws 50-with inv the ange 44, as indicatedin- Fig; 5V of the drawing, saidstubs 48- extending outwardlyfrom the flange. 44-` between the rotatable elements 42;. Theselstubs 48, accordingly, serve to separate' the elements` 42.. and: project beyondV that faceof the race. member 38.A opposite toflange 44.

Eig. 2-.of thedrawing, also, illustrates-.the way in which the flange. 44. of rotatablemembercooperates with the shaft 20- andthe racemember 38 in holding the rotatable elements- 42 against displacement in. one direction with` respect tobody III; It is to beunderstood.- that the three stubs4 48 carried. by flange 4 4:- are free to, rotate with the member 3,0 within the race 46 end-.abeut 01twith the Shaft 2.0,.V

The. outermost free ends of` the stubs, 48,' o pposite to their, peint, of. Generation; with-.11eme 44kl receivel a. Second, race member 5.2.5 haring an A loose fit is provided for member outside diameter appreciably less than the in side diameter of body IIJ and disposed between the plug I2 and the race member 38 within body II. This member 52 is provided with a race 54 that circumscribes the shaft 20 and receives a plurality of rotatable elements 56 in the nature of spheres, as illustrated, there being three of these members 56 within race 54 as shown by Fig. 3 of the drawing.

This race member 52 is supported by the stubs 48, there being openings 58 provided in the race member 52 for receiving reduced ends of the stubs 48. The race member 52, also, has a bore 60 formed therein appreciably larger than any part of the shaft 20 for circumscribing and clearing the latter.

The innermost face of the plug I2 is provided with a phu'ality of openings 62 having press tted 'therein a like number of pins 64 that project inwardly into body I6 between the rotatable elements 56. Obviously, there are three of these pins 64 for` separating the three ele-ments 56, as clearly illustrated in Fig. 3 of the drawing. Pins 64 are disposed in circumscribing relationship about shaft 2i)V and so arranged as to permit free rotation of the race member 52 thereabout.

As clearly illustrated in Fig. 2 of the drawing, the sha-ft 2U terminates at its innermost end in spaced relationshiptothe plug I4 and projects intov the bushing 32- forl free rotation there in. The shaft Z- is provided with a boss 66 intermediate its ends and, more specifically', between the two sets of rotatable elements 42 and 56. This boss S5- consti-tutes an enlarged portion or a portion ofgreater diameter on shaft 20 and merges with the lengths of lesserdiameter of shaft 20.- th-rough bevel-led portions 68 and 1Q, respectively.

Assuming all parts of the device to be formed andv arranged as above set forth, the operation is as follows:

Remembering that body I0` is freely reciprocable relative to the shaft 20; through the sliding connection between shaft 2D and bushing t8; as well as between the innermost end of' the shaft 20( and bush-ing 32, such relative movement of bod-y I0 in one direction willy movev elements 42 into frictional engagement with bevelled por.- tions4 7-0' ofshaf-t- 2Il,` and' relative movement of body I=0in the opposite direction will' move el'ements 56 into frictional' engagement with the bevelled portions 68 of shaft 20.

Fig; lof thedrawings showsA oneV way of mounting theV device through use of; a clamp I2 in ciroumscribingengagement with body I0: Clamp T2 has apair ofL opposedfingers 'I4- loosely embracing post I6 ofdr-illpress- 23:

Assuming first that drillI press 23; is manipulated tomove tap 38; into engagement withL work 181 on table- Silj, clamp 'I2A will'. move; with body I-0f while preventing rotation thereof; Bevelled portion 'f of shaft 2.5 will move into frictionall en-l gagement-with elements 42, whereupon rotation of. shaft 29 inA one direction will' cause elements 42: to.move therewith, since-body I Il-isbeing'held againsty rotation. Suchi movement ofy thel elements 42.- as. a unit Willi rotate-the member- 30'fin the same direction. as. the; rotation of: shaft 2U- because of theengagement. of: elements 42 witlr the stubs.. 48a

Consequently, shaft 20, elements 42, stubs 48; flange- Ih'', rotatable member- 3D1 and shaft' 34:- will; allgrotate in. the same direction: as a1 unit'as body; I0, race member 38 and plug I4 are held against? rotation It is;to,be rememberedthat the tubular 5 lmember 35 rotates within the opening 28 of plug I4.

Obviously, rotation of the stubs 48 will, also, cause rotation of the race member 52 but, during this phase of the operation, such rotation of race member 52 is only consequential and has no effect, since elements 56 are held in a given position with respect to body I by virtue of the pins 64. Y

To rotate the chuck 3e and tool 38 carried thereby in the opposite direction to that just described, while shaft 2U rotates in the same direction as that above assumed when elements 2 are in engagement with bevelled portion 10, body Ill must be reciprocated in a direction away from chuck 22. Such movement of body Il) with respect to shaft 2li moves frictional elements 42 out of engagement with the bevelled portion 'lil of shaft 2B and is accomplished by operation of press .23 to raise chuck 22.

As the chuck 22 is continued to be moved in a direction away from body I0, the elements 5e are brought into frictional engagement with the bevelled portion 68 of shaft 20. Fig. 2 shows the way in which plug i2 cooperates with the race 5ft and shaft 253 in holding elements 56 in a circular path about shaft 2li and against the bevelled portion 68.

Here again, the body lil is held against rotation with respect to the shaft 20 and, accordingly, as shaft 253 rotated to rotate elements 5@ in the opposite direction, such elements cannot revolve as a unit about shaft 20 because of the inwardly-extending pins 64. However, since the elements 56 are rotating in a direction opposite to the rotation of shaft 2B and upon their own vertical axes, such elements 55 will cause rotation of the race member 52 in the opposite direction of rotation to that of shaft 2U.

Consequently, the chuck 36 and tool 38 will ro- L tate in a direction opposite to shaft 2i? by virtue of the connection between rotatable member 30 and the race member 52 through the stubs i8 joining flange c and race member 52.

With the body il] and the parts carried thereby positioned so as to maintain elements 5G and l2 out of engagement with bevelled portions E8 and if, respectively, there will be no rotation of the chuck 35 or tool 38 if even a small loadl is upon the tool 33. rotated by shaft 2i) when the body l0 is permitted to rotate with shaft 2li by virtue of the frictional engagement of body I0 with shaft 20.

Through actual use of the device above set forth, it has been determined that only a relatively light touch need be imparted by the operator to the body il? when bracket 12 is not used to hold body It against rotation and to, also, hold body l5 in positions for bringing either elements 42 or elements 56 into engagement with respective bevelled portions of shaft 2D. When such light touch is imparted to the body l0, there will be no breakage of the tool 38 while the shaft 2&3 rotates continuously in one direction because, the moment any binding or other obstruction takes place upon tool 38 tending to prevent its free rotation, the elements 42 or 5E, as the case may be, will slip with respect to shaft 20.

It has been determined, also, that the entire tapping operation can be speeded up tremendously through use of the driving oonnectionhereof, since the operator can quickly and easily change the directions of rotation of tool 38 by the mere manipulation of drill press 23. In other words, reciprocation of shaft 20 in one direction By the same token, tool 38 is not with respect to body I!! will cause rotation of tap 38-to form threads in the work being handled and, as soon as such operation is completed, the tap 38 may be-reinoved from the work by shifting shaft 2G in the opposite direction within body Il) and thereby rotating tool 38 in the opposite direction.

Clearly, if the device is to be used in a drill press, the operator will cause movement of chuck 22 and shaft 2@ carried thereby toward and from the work l as above set forth.

It has, also, become apparent from the foregoing that the driving connection hereof serves as a speed reducer between shafts 25 and 34. The proportion of speed reduction, of course, is dependent upon the extent of frictional engagen ment between driving elements 42 and 55 and shaft-2li and, accordingly, the extent of speed reduction is not positive.

While the driving elements 42 and 55 have been illustrated as spherical members and, while the races 55 and 5ft therefor have been formed to accommodate such shaped driving elements, it is apparent that a very effective speed reducer might be produced by varying the shapes of elements d2, 55, iii and 54. Obviously, through use of frusto conical, rotatable elements in lieu of spheres 42 and 55, together with correspond` ingly-shaped races, a more positive drive could be provided for either speed reduction or increase.

By the same token, such members might well be made to present a number of flat faces and having a hexagonal cross sectional contour, if desired.

Therefore, while but one embodiment of the present invention has been illustrated and described, the same is inherently capable of many modifications and changes in details of construction, and such alterations as fairly come within the scope of the appended claims are contemplated hereby.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

l. A driving assembly comprising a first rotatable shaft; a second rotatable shaft coaxially aligned with said first shaft; a pair of races, each having a series of rotatable elements circumscribing the axes of said shafts; structure joining one race with the second shaft and disposed within an annular path of travel of the series of elements of the other race about said axes; means for holding the series of elements of said one race against movement in an annular path about said axes; means for holding said other race against rotation;l means for holding said other race against movement toward and away from the second shaft; and means on the first shaft between the races for alternately engaging said series of elements as the first shaft is reciprocated relatively thereto on its axis whereby to selectively rotate the second shaft in opposite directions.

21. A driving assembly comprising a first rotatable shaft; a second rotatable shaft coaxially aligned with said first shaft; a body circumscribing the shafts adjacent their proximal ends and rotatable relative thereto, said body and said first shaft being relatively reciprocable on the axes of said shafts; a first race rotatable in the body; a second race rigid in the body; structure joining said first race and said second shaft for rotation as a unit; a first series of rotatable elements circumscribing said axes within the first race; a second series of rotatable elements circuinsci'ibing said axes within the second race; means in the body for holding said first series of elements against movement in an annular path with respect to the body, said structure being Within an annular path of travel of said second series of elements; and means on the first shaft, alternately engageable with said first and said second series of elements as the first shaft and the body are reciprocated relatively, for rotating the second shaft in opposite directions.

3. A driving assembly comprising a first rotatable shaft; a second rotatable shaft coaxially aligned with said rst shaft; a body circumscribing the shafts adjacent their proximal ends and rotatable relative thereto, said body and said rst shaft being relatively reoiprocable on the axes of said shaft; a first race rotatable in the body; a second race rigid in the body; structure joining7 said first race and said second shaft for rotation as a unit; a rst series of rotatable elements circumscribing said axes within the first race; a second series of rotatable elements cir cumscribing said axes within the second race; means in the body for holding said first series of elements against movement in an annular path with respect to the body, said structure being Within an annular path of travel of said second series of elements; and means on the rst shaft, alternately engageable with said first and said second series of elements as the first shaft and the body are reciprocated relatively, for rotating the second shaft in opposite directions, said second race circumscribing a portion of said structure.

4. A driving assembly comprising a first rotatable shaft; a second rotatable shaft coaxially aligned with said shaft; a body circumscribing the shafts adjacent their proximal ends and rotatable relative thereto, said body and said first shaft being relatively reciprocable on the axes of said shafts; a first race rotatable in the body; a second race rigid in the body; structure joining said first race and said second Vshaft for rotation as a unit; a rst series of rotatable elements cir- .f

cumscribing said axes within the rst race; a second series of rotatable elements circumscribing said axes within the second race; means in the body for holding said first series of elements against movement in an annular path with respect to the body, said structure being within an annular path of travel of said second series of elements; and means on the first shaft, alternately engageable with said rst and said second series of elements as the first shaft and the body are reciprocated relatively, for rotating the second shaft in opposite directions, said means on the rst shaft comprising a boss having opposed, annular, inclined surfaces.

5. A driving assembly comprising a rst rotatable shaft; a second rotatable shaft coaxially aligned with said first shaft; a body circumscribing the shafts adjacent their proximal ends and rotatable relative thereto, said body and said first shaft being relatively reciprocable on the axes of said shafts; a nrst race rotatable in the body; a second race rigid in the body; structure joining said first race and said second shaft for rotation as a unit; a rst series of rotatable elements circumscribing said axes Within the first race; a second series of rotatable elements circumscrib ing said axes within the second race; means in the body for holding said first series of elements against movement in an annular path with respect to the body, said structure being within an annular path of travel of said second series of elements; and means on the ilrst shaft, alternately engageable with said first and said second series of elements as the first shaft and the body are reciprocated relatively, for rotating the second shaft in opposite directions, said second race circumscribing a portion of said structure, said structure comprising a number of pins on the rst race and an out-turned ange on the second shaft for receiving the pins.

EARL M. KURTZ. JOSEPH B. HOUSTN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 597,311 Busch Jan. l1, 1898 1,399,442 Rennerfelt Dec. 6, 1921 '1,995,171 Coffee Mar. 19, 1935 2,095,279 Newman Oct. l2, 1937 FGREGN PATENTS Number Country Date 794,188 France Dec. 2, 1935 

